@incollection{schiffer2005a,
  author = {Schiffer, S.},
  date = {2005},
  title = {Die Darstellung des Islams in der Presse: Sprache, Bilder, Suggestionen},
  publisher = {Ergon},
  booktitle = {Eine Auswahl von Techniken und Beispielen},
  address = {Würzburg},
  language = {german}
}

Both title and booktitle converted to sentence case:
@incollection{albrecht2007a,
  author = {Albrecht, C.},
  date = {2007},
  title = {Evangelische Publizistik},
  editor = {Malik, J./Rüpke and J./Wobbe, T.},
  publisher = {Aschendorff},
  pages = {153 – 163},
  booktitle = {Religion und Medien: Vom Kultbild zum Internetritual},
  address = {Münster}
}

Title capitalization preserved, but booktitle converted to sentence case
@incollection{gaertner2008a,
  author = {Gärtner, C.},
  date = {2008},
  title = {Die Rückkehr der Religionen in der politischen und medialen Öffent­ lichkeit},
  editor = {Gabriel, K./Höhn and H.-J.},
  publisher = {Schöningh},
  pages = {93 – 108},
  booktitle = {Religion heute – öffentlich und politisch: Provokationen, Kontroversen, Perspektiven},
  address = {Paderborn}
}

Capitalization for both title and booktitle preserved.
@incollection{schiffer2005b,
  author = {Schiffer, S.},
  date = {2005},
  title = {Die Darstellung des Islams in der Presse: Sprache, Bilder, Suggestionen},
  publisher = {Ergon},
  booktitle = {Eine Auswahl von Techniken und Beispielen},
  address = {Würzburg},
  language = {german}
}
